Magnetoresistance of a quantum dot with spin-active interfaces

Abstract

We study the zero-bias magnetoresistance MR of an interacting quantum dot connected to two ferromagnetic leads and capacitively coupled to a gate voltage source Vg. We investigate the effects of the spin-activity of the contacts between the dot and the leads by introducing an effective exchange field in an Anderson model. This spin-activity makes easier negative MR effects, and can even lead to a giant MR effect with a sign tunable with Vg. Assuming a twofold orbital degeneracy, our approach allows to interpret in an interacting picture the MR(Vg) measured by S. Sahoo et al. [Nature Phys. 2, 99 (2005)] in single wall carbon nanotubes with ferromagnetic contacts. If this experiment is repeated on a larger Vg-range, we expect that the MR(Vg) oscillations are not regular like in the presently available data, due to Coulomb interactions.

9 pages, 6 figures, to appear in Phys. Rev. B

References in corpus (11)

• Orbital Kondo effect in carbon nanotubes
• Non-collinear Magnetoelectronics
• Kondo effect in quantum dots coupled to ferromagnetic leads
• NRG study of the Kondo effect in the presence of itinerant-electron ferromagnetism
• Four-electron shell structures and an interacting two-electron system in carbon nanotube quantum dots
• Gate-controlled spin-splitting in quantum dots with ferromagnetic leads in the Kondo regime
• Electronic Transport Spectroscopy of Carbon Nanotubes in a Magnetic Field
• Electronic excitation spectrum of metallic carbon nanotubes
• Nonequilibrium Kondo Effect in a Quantum Dot Coupled to Ferromagnetic Leads
• Spin Current and Current-Induced Spin Transfer Torque in Ferromagnet-Quantum Dot-Ferromagnet Coupled Systems
• Giant magnetoresistance of multiwall carbon nanotubes: modeling the tube/ferromagnetic-electrode burying contact

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• Spectroscopy and critical temperature of diffusive superconducting/ferromagnetic hybrid structures with spin-active interfaces
• Spin transport across carbon nanotube quantum dots
• Spin diode based on a single-wall carbon nanotube
• Transport through single-wall metallic carbon nanotubes in the cotunneling regime
• Theory of shot noise in single-walled metallic carbon nanotubes weakly coupled to nonmagnetic and ferromagnetic leads
• Conductance and current noise of a superconductor/ferromagnet quantum point contact
• Theory of a Magnetically-Controlled Quantum-Dot Spin Transistor
• Saturation of Spin-Polarized Current in Nanometer Scale Aluminum Grains
• Shot noise and tunnel magnetoresistance in multilevel quantum dots: Effects of cotunneling
• Spin-polarized transport through weakly coupled double quantum dots in the Coulomb-blockade regime
• Spin transport properties of a quantum dot coupled to ferromagnetic leads with noncollinear magnetizations
• Multi-terminal spin-dependent transport in ballistic carbon nanotubes
• Modeling a Schottky-barrier carbon nanotube field-effect transistor with ferromagnetic contacts